(1)___________________________________________________________
(2)___________________________________________________________
(3)___________________________________________________________
(1)___________________________________________________________
(2)___________________________________________________________
(3)___________________________________________________________
解析:(1)由图A可见亮斑在坐标原点上方,故应先将“竖直位移”旋钮逆时针旋转,把光斑调到坐标原点.
(2)要使荧光屏上的亮斑变成亮线,应将“扫描范围”旋钮由“外X”挡调到较高频率挡.
(3)要使B图中的亮线变长应将“X增益”旋钮顺时针旋转.